Tube-splicing method



l i l l v l Origina Filed July 14, 1925 3 Sheets-Sheet l. f

Y 1,637,466 Aug- 2 1927 E. w. BIERMAN TUBE SPLICING METHOD Original Filed July 14. 1925 3' Sheets-Sheet 2 22 VW w f8- INVENTOR Je ATTORNEY .1', n 2 C Qms 1927 E. w. BIERMAN Tum sPLIcING METHOD uriginal Filed July 14. 1925 3 Sheets-Sheet .3

,hh ATTORNEY Y Patented Aug. 2, 1927.

UNITED lSTATES PATENT oFFifcE.

3DWIN W- HERMAN. 0F KEOKUK, IOWA, Assrcmonl To STANDARD Form Trang@ yor' xnoxux, IOWA, A CORPORATION or roWA. ,j .f i* f TUBE-BPLICING METHOD.

Driginal application Med. July 14, 1925, Serial No. 43,453. Divided and ythis application med April y1'?,

. f 1926. Serial No. 102,641. f f

My present invention relates to vulcanizing) the splices of endless or annular tubes of ru ber or the like, such as' the inner tubes commonly used in automobile tires. It includes an improved method of folding or culling the endless tube prior toits introduction into the vulcanizing machine.

The apparatus employed includes a steam heated tube-enclosing mold that is substantially rigid, in combination with an elastic or non-positively operating expander which fits within the cuil' of the tube and presses the splice outward into firm engagement with the inner surface of the mold.

Preferably the expander is in the nature of a flexible pneumatic tube or bag. The mold is steam jacketed throughout the major portion of its periphery and has a slot in one Wall thereoi through which the endless tube is entered, saidslot being subsequently closed by a metallic key member, the inner end of which follows the curvature of the steam heated walls of` the mold. This key becomes highly heated by conduction from' the mold Walls so that the entire annular splice 'is subjected tol a substantially uniform temperature as Well as a uniform pressure.

The folding or cutting part of the method is extremely expeditious and simple, the

I0 tubes being made endless by splicing in any of the usual ways, are delivered to the mold in properly folded position and readily inserted thereinto with the annular splice in contact through its length with the mold u walls.

The preferred method of culling includes inserting the endless tube in deflated condition through a narrow slot in an approximately cylindrical mandrel, inflating the tube, folding the tube back over the mandrel to form a two-ply cuff, with the splice on the outer surface thereof, then detlating the tube and removing the same from the mandrel.

.For the vulcanizing part of the method,

5 the expander is run into the cuff and separated from the hot mold walls by two plies of tubing throughout a semi-circumference and four plies of tubing throughout the other Selm-circumference.

5 The invention may he more fully under- Stood from the following description in connection with kthe accompanying drawings wherein: .e i

1 is a plan view of the apparatus;

Fig. 2 `is a longitudinal sectionthere- 55 through on the line 2-2 ofy Fig. 1;

Fig. 3 is a transverse section on 3--8 ofFig-2; i

Fig. 4 is a perspective view vofthe, expander; f f y i f Fig. 5 is a perspectiveviewof the -cuing mandrel; and u Figs. 6, 7 and 8 are lperspectiveviews illus tratmg successive stepsin 4the `operation of` culling the tube. A y y In these drawings the 4vulcani'zing mold is shown as comprising y.a steam chest 10,' 'provided'with inlet pipe 11 and outlet pipe 12, having a cylindrical inner Wall 13 which forms the hot mold surface against which the tube splice is adapted to `be held. The tube isentered into the mold through a slotl Y 14 in the top thereof. This slot 1s shouldered as at 15 and tapered at 16 nearits outer end. f

A lever 17 pivoted on a pin 18 connecting a pair of ears 19 risingv from the top of the mold carries at its. intermediate portion a. key or filler 2O for closing the slot 14, this key including'ears 20 pivotedvon a pin 21 carried by the lever. v. The keyis sha d to tit the shouldered slot yand the tapere walls 15 readily guide the ,key into` lace as the lever is swung in position of PEigzB. The key is thin enough to be easily heatedfto the required temperature by conduction from the steam heated mold, but may be hollow and itself heated, if desired.

The freeend of the lever is threadedy at 22, to accommodate `locking nut provided with a handle 24, whereby the nut may `.be rotated into clamping engagement with blocks 25 rising from the top of theJ steam chestto lock the lever and thereby the key, in the closed position.l i

Cooperating with the mold to clamp a tube, is an expanding device including an air bag Q6. preferably ofheavy rubber with square. molded ends` afforded by two cup members, one forming the entireA mandrel surface and the other being coned and vulcanized therein as shown at w, Fig. 2. This the line air bag is formed with apair of spaced is mounted onthe end of af longitudinally extendin tubular member having a handle 31 and ormed at one end with a nipple 28 to which an air hose-29 is coufpled and it has the air passage- 30 extending rom the nipple to the other end which connects with the stem 27a that carries the air bag 26. The sectins 27 and 27? are connected by couplingmember 32 in which I mount a manually operable valve 33 for controlling the air passage 30. Preferably this is a three port valve' adapted Ato relieve pressure through vent 30EL whenturned to cut olf the air supl pglbe section' of the stem which carries the o positely facing 'external flanges 34, the Faces of which' are ribbed as at 35 and coact with similarly ribbed flanges 36 to clamp the ends of the air bag. Lock nuts 37 around the .threaded kstem 27 retain the clamping nuts 36 in place and if desired, the end of the vstein may receive a threaded boss or nut 38 and the thread on which the latter screws.

having a smooth outer surface to protect the softrubber of the tube and splice from contact with the corners of clamping nut 37 The complete method of splicing includes properly cuiiing'the endless tube prior toits insertion into the mold and prior to the insertion of theexpander within the tube.

The cuiling mandrel is shown in perspective in Fig. '5 wherein it will be noted that it includes a substantially cylindrical end 40 constituting a folding guide and narrow lon ltudinally extending slotl 41 therein, the en corners of which are curved as at 42 to prevent catching or tearing the tubes. Ashank 43 forms an extension of one side of the cylindrical end 40 and. terminates in y a handle member 44 of approximately semicircular cross-section. As seen in Fig. 6, the slot 41 permits adefiated endless tube 45 to be readily inserted -within the cylindrical folding guide 40. 'After the tube has kbeen inserted, it is iniiatedas in Fig. 7 through the usual air valvey 4 6, the uncured initial splice being of course firm enough to permit this. This inflation makes the foldin or cuiling operation very eas and the tu e is folded back over the outside of the foldin guide 40 in such amanner that the splice 4 therein is dis osed on the outside. of the double Vply cus.' The tube is then deiiated and the mandrel slipped out.

The properly cuied tube is inserted through the slot l14 into the vulcanizing mold.

The lever 17 lis then closed, swinging the key into operative position to close the mold. The handle 24 is rotated to lock'the lever. The ex anding air bag is then inserted into the cu ed tube as seen most clearly in Fig. 42.

After the 4 expander has been inserted within thejtube, the valve is turned to admit compressed air and any desired degree of l pressure ma be, obtained to elastically clamp the sp ice or weld against the heated rotated, the lever swung upward to remove the key and the tube withdrawn through the slot 14. L Y It will be noted that throughout a semicircuinference of the mold'there is only one thickness of rubber between the splice and the air bag,- while there are three plies of rubber between the bag andv the splice throughout the other semi-circumference'of the cuff tube. But an important feature of my invention is that this will be immaterial so far as exerting proper pressure on the splice is concerned because the cylindrical portion of the expander is of heavy highly resilientrubber with fabric reenforced ends, and the pressure exerted at the surface ofthe mold 13 by the cylindrical portion is substantially the same whether exerted through two or four thicknesses of the rubbertubing.

i. It is a fact, however, that considerably more heat from the mold 13 reaches therubber mandrel 26 through the two plies than through the four plies. In course of time this heat tends to cause devulcanization of the rubber bag ofthe expanding mandrel so that if the valve is placed always in the upright position shown in the drawings, the upper side being always exposed to the greater heat coming through the two plies of the tube, will devulcanize much the faster and the mandrel bag will become warped.

Hence, when assembling, the valve side should be turned downward as often as upward and in many cases I findfit 1desirable to eliminate the valve at this point and locate it back in the line leading to the hose 29. Then the operator will have yno incentive to insert the mandrel one side up and naturally it will'average out that all sides are used uppermostap roximately the same number of times an whatever devulcanizing will be symmetrical and will not warp the bag out of shape.

The method hereinafter claimed comprises subject matter originally claimed in my prior application, Ser. No. 43,453, iiledJuly 1 4, 1925, of which this application is a divisionaand it is to be understood that the various implements'described herein as useful in the preferred practice of my method, are claimed insaid prior application and in Ser. No. 102,642, nieu April 17,1926.

I claim:

1. A method of curing tube splices which includes foldingr the tube upon itself' to form a two-plycud' surrounding a section of the tube and with the splice in the outer ply of the cuil", inserting the cufed tube cuff and through its other semi-circumference b the two plies of the cuff and the two plies of tubing which are enclosed with- -in the cuil', and operating the expander to firmly press the splice into engagement with the hot walls of the mold.

2. A method of curing splices of. endless inner tubes, which includes placing a portion of the tube adjacent the splice within a cylindrical cufln mandrel while the tube is in deflated con ition, inflating the. tube, folding the inflated tube over the outside of the mandrel to form a two-ply cuil' with the splice in the outside ply, deflating the tube and withdrawing the mandrel; then vulcanizing said s lice b inserting the' cuil' portion of the tu wit iin a heated mold with an expander within the cuil and operating the expander lto firmly press the splice into engagement with the hot walls of the mold.

3. The method of splicing rubber inner tubes for tires, which includes cementing the ends of each tube to form an endless tube or annulus, folding the tube upon itself to form a tube-like cuil" surrounding a section of the tube and with the splice in the outer ply of the cuil'. inserting the cutfed tube Within a heated mold and inserting a rubber expander within the cuff in such manner that the expander is surrounded tor a semi-circumference only by the two plies of the cuff and through its other semi-circumference by the two plies of the cull' and the two plies of tubing ywhich are enclosed Within the cuif, and inilating the rubber expander to firmly press the splice into engagement with the hot walls of the mold, removing said tube when the splice lias'--been vulcanized by the heat and repeating said."

method with respect to each of the spliced tubes but, for different tubes, inserting the expander so that dil'erent portions of its rubber surface will be exposed to the heat conducted through the two-ply semi-circumference of the cuil'.

4. A method of splicing inner tubes which includes inserting a section of the tubing through a slot in a cylindrical folding guide while the tube is in deflated condition, inflatin the tube, folding the tube over the outsi e of the cylindrical folding, guide to form a twoply cuff on the exterior of said guide, deflating the tube and removing the cuffed tube from the guide; then inserting the cufed tube within a heated mold and inserting an expander within the cuff in such a manner that the expander is sur-- rounded for a semi-circumference only by the two plies of the cull` and through its other cemi-circumference by the two plies of the cuff and the two lies of tubin which enclosed within the cu and operatmg the expander to firmly press the splice into engagement with the hot walls of the mold.

5. A method of splicing tubes which includes placing a portion of the tube adjacent thesnlice within a cylindrical culling mandrel while the tube is in deflated condition, inllating the tube, folding the inflated tube over the outside of the mandrel to form a two-ply cult with the splice in the outside ply, deflating the tube and withdrawing the mandrel; then inserting the culed tube within a hea-ted mold and inserting an eX- pander within the cuff in such a manner that the expander is surrounded for a semicircumference only by the two plies ofthe cuff and through its other semi-circumfer ence by the two plies of the cuff' and the two plies of tubing which are enclosed within the cuff, and operating the expander to firmly press the splice into engagement with the hot walls of the mold. A

Signed at Keokuk in the county of Lee, and State of Iowa., this 14th day of April,

EDWIN W. BIERMAN. 

